August 12, 1886 – Former bank robber Sam Colby and his two partners intend to ambush and rob an army payroll wagon using a stolen Gatling gun. After setting their trap, Colby rides into Tombstone to purchase as much ammunition as he can and comes into contact with Harris Claibourne and his former fiancĂ© Sarah Medford. Colby’s violent actions bring him to the attention of Sheriff Clay Hollister who has serious concerns about Colby and the real reasons behind his visit.